Innervation of the heart. Clinical Anatomy of the Heart
The innervation of the heart and its physiological characteristics are information without which it will be difficult to clearly represent all aspects of the work of this important organ in the human body. It is interesting enough to know how the brain communicates with the center of the circulatory system in our body. In addition, the structure and principles of cardiac function also deserve attention.
The work of the heart
The heart, one might even say, the central organ of the circulatory system of the human body is the heart. It is hollow, has the shape of a cone and is located in the chest cavity. If we describe its function using extremely simple images, then we can say that the heart works like a pump, so that the blood flow necessary for the full functioning of the body remains in the complex system of arteries, vessels and veins.
Interesting is the fact that the heart can produce its own electrical activity. A quality is defined as an automaton. This feature allows even an isolated cell of the heart muscle to contract in itself. This quality is extremely important for the stable functioning of this body.
Features of the structure
Initially, the heart diagram makes you pay attention to where this organ is located. It is located, as it was written above, in the chest cavity, and so that the smaller part of it is localized on the right, and the larger part, respectively, on the left. So it's wrong to think that the whole heart is on the left side of the chest.
But more precisely, the place where the heart is located is a mediastinum, in which there are two so-called floors - the lower and upper.
The heart size is on average equal to the volume of the brush, which is compressed into a fist. It is worth knowing that the heart is divided by a special septum into two halves - left and right. In turn, each of these parts has such divisions as the ventricle and the atrium, between which there is an opening. It is closed by means of a leaf valve. The peculiarity of this valve is its structure: in its right part it has three leaves, and in the left - two.
In this case, it is a cavity, on the inside of which there are many muscle beams. There are also papillary muscles. It is from them that the tendinous threads go to the valve that closes the opening between the right ventricle and the right atrium.
With regard to the valve, its structure includes three valves, lined with an endocardium. As soon as the right ventricle contracts, this valve closes the hole, which eventually blocks the reverse flow of blood. By the way, it is from this part of the heart that the pulmonary trunk goes to the respiratory organ. Venous blood moves along it.
If you compare it with the right one, it should be noted that in this case the wall is noticeably thicker. Paying attention to the inner surface of its wall, you can see the muscle bars and papillary muscles. It is from them that the tendon threads leave, which are fixed on the edges of the left atrioventricular valve.
The left ventricle of the heart is also the place from which the largest arterial trunk, called the aorta, emerges. It is above the valve of this trunk that there are holes leading to the coronary arteries feeding the heart.
It is important to know that all arterial blood enters the left atrium and already from here gets to the left ventricle, which was discussed above. As you can see, all the heart elements are closely related and if a failure occurs in one of them, it will affect the whole organ.
Speaking about the vessels through which the blood supply of the heart is carried out, it is worth noting that they pass on the outside of the organ in special grooves. And, there are those that enter the heart, and those that come out of it.
There are also longitudinal interventricular grooves on the inferior and anterior ventricular surface. In total there are two such furrows - the posterior and anterior, but both are directed towards the apex of the organ.
Do not forget about the coronal sulcus, which is located between the lower and upper chambers. The right and left coronary arteries of the heart, or rather, their branches, are located exactly in it. Their mission is to feed the body with blood. That's why if a cholesteric plaque forms in this area or a thrombus enters there, a person's life is under threat.
In this case, there are also other large arteries of the heart, as well as venous trunks that leave this organ.
Valves These elements are attached to the so-called skeleton of the heart, which consists of two fibrous rings. Those, in turn, are located between the upper and lower chambers.
There are only 4 valves in the human heart.
The first( conditionally) is called right atrioventricular, or tricuspid. Its main function is to block the possibility of reverse blood flow from the right ventricle.
The next, the left valve, has only two leaves, which is why it got the corresponding name - bivalve. It can also be called a mitral valve. It is necessary to form a damper that does not allow blood to flow from the left atrium into the left ventricle of the heart.
The third valve - without it the opening of the pulmonary post would remain open. This would lead to the flow of blood back into the ventricle.
The heart circuit also includes the fourth valve, which is in the place where the aortic outlet is located. It does not allow the blood flow back to the heart.
What you should know about the conducting system
Blood supply to the heart is not the only function on which the stable functioning of this body depends. The formation of palpitations is extremely important. It is thanks to the conductive system that a contraction of the muscular layer is created, which serves as the beginning of the main organ of the circulatory system.
It is important to note the fact that the sinus-atrial node is the place in which the impulse is generated, which gives the command to contract the heart muscle. As for the location of its location, it is located where the hollow vein passes into the right atrium.
The structures described above have an impact on the heart, through which the following processes become possible:
- coordination of ventricular and atrial contractions;
- rhythmic generation of pulses;
- synchronous involvement of all cells of the ventricular muscle layer in the contractile process( without this, increasing the effectiveness of contractions would be extremely difficult task).
Initially, it is necessary to understand what this term implies. So, innervation is nothing more than saturation of a specific part of the body with nerves for a stable and full connection with the central nervous system. In other words, it is a neural network through which the brain controls muscles and organs. Such a feature of the body can not be ignored by studying such a topic as the structure and work of the heart.
A more detailed study of this subject can begin with a fact: the process of reducing the heart muscle is controlled by both the endocrine and nervous system. At the same time, the vegetative innervation of the heart has the most direct effect on changes in the rhythm of contractions. It's about sympathetic and parasympathetic stimulation. The first increases the frequency of contractions, the second, accordingly, reduces it.
The general activities of this body are controlled by cardiac centers of the variolium bridge and medulla oblongata. From these centers, impulses are transmitted by means of sympathetic and parasympathetic nerve fibers, which affect the force of contractions, their frequency and the rate of trioventricular conduction. As for the scheme of transmission of nervous effects on the heart, here, as in any other organs, this role is played by the mediators. In the sympathetic system, this is norepinephrine, and acetylcholine is parasympathetic, respectively.
Characteristic features of cardiac innervation
The intraorganic nervous apparatus of the heart is rather complicated. It is represented by nerves that start their way from the thoracic aortic plexus and only then enter the main organ of the circulatory system, as well as the ganglia. The latter is nothing more than the accumulation of cells in the center of the apparatus mentioned above. Nerve fibers are also part of this system. Their origin they take from the cardiac ganglia. Effectively, this structure is made by effectors and receptors.
The innervation of the heart also implies the presence of sensitive fibers. They consist of spinal nodules and a vagus nerve. This group includes also vegetative motor fibers.
So, if you pay attention to such a facet of the topic under consideration as a sympathetic innervation of the heart, then it is worth paying attention to the source of these fibers. In other words, determine where they come from to the central organ of the circulatory system. The answer is quite simple: the lateral horns of the upper thoracic segments of the spinal cord.
The essence of the effect of sympathetic stimulation is reduced to the effect on the force of contraction of the ventricles and atria, which is expressed in its increase. In fact, this is a positive inotropic effect. But that's not all - the heart rate rises. In this case, it makes sense to talk about a positive chronotropic effect. And the last effect of sympathetic innervation, which should be paid attention is the dromotropic effect, namely, the effect on the interval between contractions of the ventricles and the atria.
Parasympathetic part of the
system The innervation of the heart also includes these processes. This type of fiber approaches the heart in the vagus nerve, and on both sides.
If we talk about the "right" fibers, then their function is reduced to innervation, respectively, of the right atrium as well. In the region of the sinus-atrial node they form a dense plexus. As for the left vagus nerve, the fibers that come with it come to the atrioventricular node.
Speaking of the effect that produces parasympathetic innervation of the heart, it is worth mentioning a decrease in the force of atrial contraction and a decrease in heart rate. But the atrioventricular delay increases. It is easy to conclude that the work of nerve fibers plays more than a significant role in the functioning of the circulatory system.
Against the backdrop of, perhaps, complex information about what the heart is, it makes sense to give a little attention to simple actions that will help keep it in working condition for many years.
So, considering what features the structure and work of the heart has, one can conclude that the health of this organ depends on the state of the three elements: muscle tissue, blood vessels and blood flow.
In order for everything to be good with the heart muscle, you need to give it a moderate load. This mission is perfectly performed jogging( without fanaticism) or walking. Such exercises harden the main organ of the circulatory system.
Now a little bit about the vessels. That they were in shape, you need to eat right. This means that you will have to say goodbye forever with large and stable portions of fatty foods and competently build your diet. The body should receive all the necessary nutrients and vitamins, then everything will be fine.
And the last guarantee of a long work of the heart, and the whole body, is a good blood flow. Here comes to the aid of a simple secret: all people in the evening the blood becomes thicker. And if we are talking about representatives of the middle age group, then its consistency in some cases becomes dangerous, causing a risk of heart attack or stroke. Correct the situation will help evening walks in the bosom of nature. Where there are trees, lakes, sea, mountains or waterfalls - a high concentration of ionized air, which significantly improves the fluidity of the blood.
Based on all the above information, you can come to an obvious conclusion: the innervation of the heart, the physiology of this body and its work as a whole will always be important topics that remain relevant. After all, without this knowledge, the level of which is constantly deepening, it is difficult to imagine effective diagnosis and competent treatment of the heart.